Abstract: A comprechensive analysis has been made on the chemical composition of the black liquor of Eucalyptus citriodora chips in the sulfate and soda-anthraquinone cooking process. Relatons between the concentrations of two black liquors and the content of total solids, relations between the viscosity, temperature and concentration of the black liquors as well as the amounts of carbon, oxygen, hydrogen, nitrogen, sulfur, sodium, etc. and the calorific values in the solids of the black liquors have been worked out. Data obtaidne from analysis results show that alkali recovery technique can be used inthe black liquor sulfate and soda anthraquinone cooking process.